(a) Field of the Invention
The present invention relates to a liquid crystal display, a method of manufacturing the same, and an apparatus for manufacturing the same.
(b) Description of the Related Art
Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. An LCD includes two panels provided with field-generating electrodes and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
Among LCDs that include field-generating electrodes on respective panels, a plurality of pixel electrodes arranged in a matrix are provided on one panel and a common electrode is provided covering an entire surface of the other panel. Image display of the LCD is accomplished by applying individual voltages to the respective pixel electrodes. For the application of the individual voltages, a plurality of three-terminal thin film transistors (TFTs) are connected to the respective pixel electrodes, and a plurality of gate lines transmitting signals for controlling the TFTs and a plurality of data lines transmitting voltages to be applied to the pixel electrodes are provided on the panel.
The LCD also includes at least one alignment layer for aligning the liquid crystal molecules of the liquid crystal layer in horizontal or vertical alignments from the surfaces of the panels. The alignment layer is an organic alignment layer made of a polyimide material that is printed on the panels.
However, it is difficult for the alignment layer to be printed on the panel with a uniform thickness with a large-scale panel, and alignment defects are frequently generated due to a low polyimidization ratio of the alignment layer. Also, multiple processes such as the printing of polyimide, a pre-cure, and a main-cure are required to form the organic alignment layer.
Accordingly, a technique for replacing the organic alignment layer with an inorganic alignment layer has been developed, and the inorganic alignment layer may be more easily formed than the organic alignment layer. However, expensive devices for thin film deposition process such as plasma enhanced chemical vapor deposition and sputtering are required to form the inorganic alignment layer. Also, when these devices are used, a step process for removing the deposited alignment layer to expose a short point area and a pad area for electrical connection of the upper and the lower panels and external driving circuits are required.